190 



THE AMERICAN NATURALIST [Vol. LV 



year, August 12. it was in fact a strong: colony, containing ninety- 

 one Avorkers, fifty-six pupal cocoons, and large stores of honey 

 and pollen. It is possible that the upper part of the comb of a 

 bumblebee nest might develop so swiftly in some cases, as to 

 cause some cells either filled or not filled with pollen and honey 

 on the lower part of the comb to be neglected, and thus infested 

 with Aniheropkagus. This last statement, however, would cer- 

 tainly be the exception rather than the rule. In the cases that 

 have eome under my observation A. ochraceus played the role 

 of a scavenger, in the debris beneath and about the nest, feeding 

 on the refuse comb, feces, honey, or bits of pollen and wax that 

 perchance had fallen to the bottom of the nest. 



Wheeler voices the opinion of Sharp (1899) that the instincts 

 of the beetle permit it to recognize the bumblebee, but not to en- 

 able it to find the nest. Therefore the beetle waits on flowers 

 until it can attach itself to a bumblebee and be conveyed to the 

 nest of the latter. Donisthorpe suggests that "it is not so much 

 that they {Anilur^phagiis] lack the instinct to find the bee's 

 nest, but rather that it gives them protection from their hosts 

 when they arrive there." . AntheropJiagus may or may not be 

 able to find the nests of bumblebees of its own accord, but I am 

 inclined to doul«t wliether the occasion of the "phoresy" is pro- 

 Toctive. ill tliat it gives "them protection from their hosts when 

 rliey arrivt^ Th.-iv." 1)y their having acquired the nest "aura." 

 If Anflirroitliafji's i'^ a scavenger, as the evidence seems to indi- 

 cate, and keeps well hidden in the debris on the Iwttom or sides 

 of the comb, why is there a need for a nest "aura"? One of 

 these beetles carried to a bumblebee's nest, in all probability, 

 soon after arriving there, relea.ses its hold and falls down to the 

 lower part or bottom of the nest. Many other beetles are acci- 

 dental visitors or inhabitants of such nests, and living thus in the 

 material about and beneath the comb are not noticed by the ever- 

 watchful bees and go unmolested. W. H. Tuck (1896, 1897) lists 

 over sixty species of beetles from the nests of various species 

 of bumblebees in England, most of which are undoubtedly only 

 ca.sual intruders. I have taken specimens of Harpcdus sp. and 

 Onthophrif/uf! hecate Panz. in the nests of bumblebees. Such 

 beetles are much larger than AntJierophagus, are not even con- 

 sidered as "aiitliophilous" (Lovell, 1915), nor have they ever 

 been aeeredited with habits of "phoresy." Evidently then, such 

 beetles gain entrance to the nest and live there for a time at 



